Metadata V15: Add Runtime API metadata (#13302)

* impl_runtime_apis: Generate getters for `metadata_at` functions Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * runtime: Implement new `Metadata` runtime trait Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * runtime: Move `metadata_at` functions to construct_runtime macro Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * contruct_runtime: Use `OpaqueMetadata` from hidden imports Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Adjust testing Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/tests: Add tests for the new API Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Helper to extract documentation literals Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Helper to filter all `cfg` attributes Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Generate documentation getters for metadata Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Avoid trait collision with snake case methods Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * proc-macro/tests: Check doc getters Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Generate metadata for runtime methods Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/api: Export scale-info and frame-metadata Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Generate metadata for runtime traits Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/runtime: Expose metadata v15 internally Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * test: Use metadata v15 from `lexnv/md_v15_test` branch Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Generate crate access one module up Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame: Implement `runtime_metadata` for mocks and tests Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Fix warnings Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Add no-docs flag Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame: Adjust more tests Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/tests: Check runtime metadata correctness Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/benchmarking: Adjust benchmarks Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/benchmarks: Adjust more benchmarks Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/api: Fix clippy Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/proc-macro: Generate runtime metadata on the `decl_runtime_apis` Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame: Abuse Deref to resolve `runtime_metadata` Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Revert "frame: Implement `runtime_metadata` for mocks and tests" This reverts commit b7f41aa189218589392a6e713ea9488e93c4db45. Revert "frame: Adjust more tests" This reverts commit 3cba5982c7f45552e76335e96c430aecbc42d8c6. Revert "frame/benchmarking: Adjust benchmarks" This reverts commit 60b382ada486c791ffceeb65da587e949b90ec5d. Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> Revert "frame/benchmarks: Adjust more benchmarks" This reverts commit eb75c477179b1a27347a5554c5732ef26a00d7e8. * primitives/proc-macro: Remove unused imports and function Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/support: Adjust runtime metadata test Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/tests: Remove doc getter test Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/support: Enable `no-metadata-docs` feature from `sp-api` Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/tests: Add `TypeInfo` for test::extrinsic Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/api: Expose scale-info and frame-metadata Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Update frame-metadata to include v15 Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Fix merge conflicts Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/metadata_ir: Add IR for runtime API metadata Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/metadata_ir: Convert IR to V15 Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/api: Collect IR metadata for runtime API Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/api: Move `metadata_ir` from frame/support Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/tests: Adjust testing Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame/tests: Adjust `metadata_versions` test Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/runtime_metadata: Exclude default type parameters from methods Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/src/metadata_ir/types.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/src/metadata_ir/mod.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/utils.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * primitives: Fix build Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives/metadata-ir: Move IR to dedicated crate Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives: Reexport metadata-ir and frame-metadata Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * frame: Use apis field instead of runtime Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Better documentation for the `Deref` abstraction Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * ui-tests: Check empty `impl_runtime_apis` Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives: Remove unneeded bounds on generic params Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives: Rename `collect_where_bounds` to `get_argument_type_param` Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives: Generate crate access per fn call Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Revert "primitives: Remove unneeded bounds on generic params" This reverts commit 5178e38cf21cfb481156eefd628d62989201d59a. * metadata-ir: Add no-std Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * primitives: Adjust where bounds Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Change `frame-metadata` branch to "origin/main" Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Update to `main` from origin Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Update frame-metadata to crates.io v15.1 Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Revert "ui-tests: Check empty `impl_runtime_apis`" This reverts commit cf78a7190ad9cba3c3bb2e78dc3d0dc382b2fea9. * Move ui test to primitives/ui Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Update frame/support/test/tests/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Update primitives/api/proc-macro/src/runtime_metadata.rs Co-authored-by: Bastian Köcher <git@kchr.de> * Test already covered by `empty_impl_runtime_apis_call.stderr` This reverts commit 3bafb294cbe9745569bf5e5a1a2e6b4a4c1aadc5. * Retriger CI Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> * Import `TokenStream` as `TokenStream2` Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> --------- Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> Co-authored-by: parity-processbot <> Co-authored-by: Bastian Köcher <git@kchr.de>
2026-06-12 08:51:09 +00:00 · 2023-04-11 14:07:52 +03:00
parent 17765733f0
commit 29ea9e0ad9
25 changed files with 993 additions and 31 deletions
@@ -2413,9 +2413,9 @@ dependencies = [

 [[package]]
 name = "frame-metadata"
-version = "15.0.0"
+version = "15.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df6bb8542ef006ef0de09a5c4420787d79823c0ed7924225822362fd2bf2ff2d"
+checksum = "878babb0b136e731cc77ec2fd883ff02745ff21e6fb662729953d44923df009c"
 dependencies = [
 "cfg-if",
 "parity-scale-codec",
@@ -2525,6 +2525,7 @@ dependencies = [
 "rustversion",
 "scale-info",
 "serde",
+ "sp-api",
 "sp-arithmetic",
 "sp-core",
 "sp-io",
@@ -10156,8 +10157,10 @@ dependencies = [
 "hash-db",
 "log",
 "parity-scale-codec",
+ "scale-info",
 "sp-api-proc-macro",
 "sp-core",
+ "sp-metadata-ir",
 "sp-runtime",
 "sp-state-machine",
 "sp-std",
@@ -10172,6 +10175,7 @@ name = "sp-api-proc-macro"
 version = "4.0.0-dev"
 dependencies = [
 "Inflector",
+ "assert_matches",
 "blake2",
 "expander",
 "proc-macro-crate",
@@ -10591,6 +10595,16 @@ dependencies = [
 "zstd",
 ]

+[[package]]
+name = "sp-metadata-ir"
+version = "0.1.0"
+dependencies = [
+ "frame-metadata",
+ "parity-scale-codec",
+ "scale-info",
+ "sp-std",
+]
+
 [[package]]
 name = "sp-mmr-primitives"
 version = "4.0.0-dev"
@@ -10842,6 +10856,7 @@ name = "sp-test-primitives"
 version = "2.0.0"
 dependencies = [
 "parity-scale-codec",
+ "scale-info",
 "serde",
 "sp-application-crypto",
 "sp-core",
@@ -202,6 +202,7 @@ members = [
 	"primitives/keystore",
 	"primitives/maybe-compressed-blob",
 	"primitives/merkle-mountain-range",
+	"primitives/metadata-ir",
 	"primitives/npos-elections",
 	"primitives/npos-elections/fuzzer",
 	"primitives/offchain",
@@ -16,7 +16,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 serde = { version = "1.0.136", optional = true, features = ["derive"] }
 codec = { package = "parity-scale-codec", version = "3.2.2", default-features = false, features = ["derive", "max-encoded-len"] }
 scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
-frame-metadata = { version = "15.0.0", default-features = false, features = ["v14"] }
+frame-metadata = { version = "15.1.0", default-features = false, features = ["v14", "v15-unstable"] }
 sp-api = { version = "4.0.0-dev", default-features = false, path = "../../primitives/api" }
 sp-std = { version = "5.0.0", default-features = false, path = "../../primitives/std" }
 sp-io = { version = "7.0.0", default-features = false, path = "../../primitives/io" }
@@ -74,7 +74,7 @@ runtime-benchmarks = []
 try-runtime = []
 # By default some types have documentation, `no-metadata-docs` allows to reduce the documentation
 # in the metadata.
-no-metadata-docs = ["frame-support-procedural/no-metadata-docs"]
+no-metadata-docs = ["frame-support-procedural/no-metadata-docs", "sp-api/no-metadata-docs"]
 # By default some types have documentation, `full-metadata-docs` allows to add documentation to
 # more types in the metadata.
 full-metadata-docs = ["scale-info/docs"]
@@ -77,6 +77,24 @@ pub fn expand_runtime_metadata(
 	quote! {
 		impl #runtime {
 			fn metadata_ir() -> #scrate::metadata_ir::MetadataIR {
+				// Each runtime must expose the `runtime_metadata()` to fetch the runtime API metadata.
+				// The function is implemented by calling `impl_runtime_apis!`.
+				//
+				// However, the `construct_runtime!` may be called without calling `impl_runtime_apis!`.
+				// Rely on the `Deref` trait to differentiate between a runtime that implements
+				// APIs (by macro impl_runtime_apis!) and a runtime that is simply created (by macro construct_runtime!).
+				//
+				// Both `InternalConstructRuntime` and `InternalImplRuntimeApis` expose a `runtime_metadata()` function.
+				// `InternalConstructRuntime` is implemented by the `construct_runtime!` for Runtime references (`& Runtime`),
+				// while `InternalImplRuntimeApis` is implemented by the `impl_runtime_apis!` for Runtime (`Runtime`).
+				//
+				// Therefore, the `Deref` trait will resolve the `runtime_metadata` from `impl_runtime_apis!`
+				// when both macros are called; and will resolve an empty `runtime_metadata` when only the `construct_runtime!`
+				// is called.
+				//
+				// `Deref` needs a reference for resolving the function call.
+				let rt = #runtime;
+
 				#scrate::metadata_ir::MetadataIR {
 					pallets: #scrate::sp_std::vec![ #(#pallets),* ],
 					extrinsic: #scrate::metadata_ir::ExtrinsicMetadataIR {
@@ -95,7 +113,8 @@ pub fn expand_runtime_metadata(
 								})
 								.collect(),
 					},
-					ty: #scrate::scale_info::meta_type::<#runtime>()
+					ty: #scrate::scale_info::meta_type::<#runtime>(),
+					apis: (&rt).runtime_metadata(),
 				}
 			}

@@ -296,6 +296,31 @@ fn construct_runtime_final_expansion(
 			type RuntimeBlock = #block;
 		}

+		// Each runtime must expose the `runtime_metadata()` to fetch the runtime API metadata.
+		// The function is implemented by calling `impl_runtime_apis!`.
+		//
+		// However, the `construct_runtime!` may be called without calling `impl_runtime_apis!`.
+		// Rely on the `Deref` trait to differentiate between a runtime that implements
+		// APIs (by macro impl_runtime_apis!) and a runtime that is simply created (by macro construct_runtime!).
+		//
+		// Both `InternalConstructRuntime` and `InternalImplRuntimeApis` expose a `runtime_metadata()` function.
+		// `InternalConstructRuntime` is implemented by the `construct_runtime!` for Runtime references (`& Runtime`),
+		// while `InternalImplRuntimeApis` is implemented by the `impl_runtime_apis!` for Runtime (`Runtime`).
+		//
+		// Therefore, the `Deref` trait will resolve the `runtime_metadata` from `impl_runtime_apis!`
+		// when both macros are called; and will resolve an empty `runtime_metadata` when only the `construct_runtime!`
+		// is called.
+
+		#[doc(hidden)]
+		trait InternalConstructRuntime {
+			#[inline(always)]
+			fn runtime_metadata(&self) -> #scrate::sp_std::vec::Vec<#scrate::metadata_ir::RuntimeApiMetadataIR> {
+				Default::default()
+			}
+		}
+		#[doc(hidden)]
+		impl InternalConstructRuntime for &#name {}
+
 		#outer_event

 		#outer_origin
@@ -50,6 +50,7 @@ pub use paste;
 pub use scale_info;
 #[cfg(feature = "std")]
 pub use serde;
+pub use sp_api::metadata_ir;
 pub use sp_core::{OpaqueMetadata, Void};
 #[doc(hidden)]
 pub use sp_core_hashing_proc_macro;
@@ -80,7 +81,6 @@ pub mod error;
 pub mod crypto;
 pub mod dispatch_context;
 pub mod instances;
-pub mod metadata_ir;
 pub mod migrations;
 pub mod traits;
 pub mod weights;
@@ -15,6 +15,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 serde = { version = "1.0.136", default-features = false, features = ["derive"] }
 codec = { package = "parity-scale-codec", version = "3.2.2", default-features = false, features = ["derive"] }
 scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+sp-api = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/api" }
 sp-arithmetic = { version = "6.0.0", default-features = false, path = "../../../primitives/arithmetic" }
 sp-io = { version = "7.0.0", path = "../../../primitives/io", default-features = false }
 sp-state-machine = { version = "0.13.0", optional = true, path = "../../../primitives/state-machine" }
@@ -47,6 +48,7 @@ std = [
 	"sp-state-machine",
 	"sp-arithmetic/std",
 	"sp-version/std",
+	"sp-api/std",
 ]
 try-runtime = ["frame-support/try-runtime"]
 # WARNING:
@@ -1671,7 +1671,7 @@ fn metadata_at_version() {

 #[test]
 fn metadata_versions() {
-	assert_eq!(vec![LATEST_METADATA_VERSION], Runtime::metadata_versions());
+	assert_eq!(vec![LATEST_METADATA_VERSION, u32::MAX], Runtime::metadata_versions());
 }

 #[test]
@@ -0,0 +1,222 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use frame_support::{
+	metadata_ir::{
+		RuntimeApiMetadataIR, RuntimeApiMethodMetadataIR, RuntimeApiMethodParamMetadataIR,
+	},
+	traits::ConstU32,
+};
+use scale_info::{form::MetaForm, meta_type};
+use sp_runtime::traits::Block as BlockT;
+
+pub type BlockNumber = u64;
+pub type Index = u64;
+pub type Header = sp_runtime::generic::Header<u32, sp_runtime::traits::BlakeTwo256>;
+pub type Block = sp_runtime::generic::Block<Header, UncheckedExtrinsic>;
+pub type UncheckedExtrinsic = sp_runtime::generic::UncheckedExtrinsic<u32, RuntimeCall, (), ()>;
+
+impl frame_system::Config for Runtime {
+	type BlockWeights = ();
+	type BlockLength = ();
+	type DbWeight = ();
+	type BaseCallFilter = frame_support::traits::Everything;
+	type RuntimeOrigin = RuntimeOrigin;
+	type Index = u64;
+	type BlockNumber = u32;
+	type RuntimeCall = RuntimeCall;
+	type Hash = sp_runtime::testing::H256;
+	type Hashing = sp_runtime::traits::BlakeTwo256;
+	type AccountId = u64;
+	type Lookup = sp_runtime::traits::IdentityLookup<Self::AccountId>;
+	type Header = Header;
+	type RuntimeEvent = RuntimeEvent;
+	type BlockHashCount = ConstU32<250>;
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = ();
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type SystemWeightInfo = ();
+	type SS58Prefix = ();
+	type OnSetCode = ();
+	type MaxConsumers = ConstU32<16>;
+}
+
+frame_support::construct_runtime!(
+	pub enum Runtime where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic
+	{
+		System: frame_system,
+	}
+);
+
+sp_api::decl_runtime_apis! {
+	/// ApiWithCustomVersion trait documentation
+	///
+	/// Documentation on multiline.
+	pub trait Api {
+		fn test(data: u64);
+		/// something_with_block.
+		fn something_with_block(block: Block) -> Block;
+		fn function_with_two_args(data: u64, block: Block);
+		fn same_name();
+		fn wild_card(_: u32);
+	}
+}
+
+sp_api::impl_runtime_apis! {
+	impl self::Api<Block> for Runtime {
+		fn test(_data: u64) {
+			unimplemented!()
+		}
+
+		fn something_with_block(_: Block) -> Block {
+			unimplemented!()
+		}
+
+		fn function_with_two_args(_: u64, _: Block) {
+			unimplemented!()
+		}
+
+		fn same_name() {}
+
+		fn wild_card(_: u32) {}
+	}
+
+	impl sp_api::Core<Block> for Runtime {
+		fn version() -> sp_version::RuntimeVersion {
+			unimplemented!()
+		}
+		fn execute_block(_: Block) {
+			unimplemented!()
+		}
+		fn initialize_block(_: &<Block as BlockT>::Header) {
+			unimplemented!()
+		}
+	}
+}
+
+#[test]
+fn runtime_metadata() {
+	fn maybe_docs(doc: Vec<&'static str>) -> Vec<&'static str> {
+		if cfg!(feature = "no-metadata-docs") {
+			vec![]
+		} else {
+			doc
+		}
+	}
+
+	let expected_runtime_metadata = vec![
+		RuntimeApiMetadataIR {
+			name: "Api",
+			methods: vec![
+				RuntimeApiMethodMetadataIR {
+					name: "test",
+					inputs: vec![RuntimeApiMethodParamMetadataIR::<MetaForm> {
+						name: "data",
+						ty: meta_type::<u64>(),
+					}],
+					output: meta_type::<()>(),
+					docs: vec![],
+				},
+				RuntimeApiMethodMetadataIR {
+					name: "something_with_block",
+					inputs: vec![RuntimeApiMethodParamMetadataIR::<MetaForm> {
+						name: "block",
+						ty: meta_type::<Block>(),
+					}],
+					output: meta_type::<Block>(),
+					docs: maybe_docs(vec![" something_with_block."]),
+				},
+				RuntimeApiMethodMetadataIR {
+					name: "function_with_two_args",
+					inputs: vec![
+						RuntimeApiMethodParamMetadataIR::<MetaForm> {
+							name: "data",
+							ty: meta_type::<u64>(),
+						},
+						RuntimeApiMethodParamMetadataIR::<MetaForm> {
+							name: "block",
+							ty: meta_type::<Block>(),
+						},
+					],
+					output: meta_type::<()>(),
+					docs: vec![],
+				},
+				RuntimeApiMethodMetadataIR {
+					name: "same_name",
+					inputs: vec![],
+					output: meta_type::<()>(),
+					docs: vec![],
+				},
+				RuntimeApiMethodMetadataIR {
+					name: "wild_card",
+					inputs: vec![RuntimeApiMethodParamMetadataIR::<MetaForm> {
+						name: "_",
+						ty: meta_type::<u32>(),
+					}],
+					output: meta_type::<()>(),
+					docs: vec![],
+				},
+			],
+			docs: maybe_docs(vec![
+				" ApiWithCustomVersion trait documentation",
+				"",
+				" Documentation on multiline.",
+			]),
+		},
+		RuntimeApiMetadataIR {
+			name: "Core",
+			methods: vec![
+				RuntimeApiMethodMetadataIR {
+					name: "version",
+					inputs: vec![],
+					output: meta_type::<sp_version::RuntimeVersion>(),
+					docs: maybe_docs(vec![" Returns the version of the runtime."]),
+				},
+				RuntimeApiMethodMetadataIR {
+					name: "execute_block",
+					inputs: vec![RuntimeApiMethodParamMetadataIR::<MetaForm> {
+						name: "block",
+						ty: meta_type::<Block>(),
+					}],
+					output: meta_type::<()>(),
+					docs: maybe_docs(vec![" Execute the given block."]),
+				},
+				RuntimeApiMethodMetadataIR {
+					name: "initialize_block",
+					inputs: vec![RuntimeApiMethodParamMetadataIR::<MetaForm> {
+						name: "header",
+						ty: meta_type::<&<Block as BlockT>::Header>(),
+					}],
+					output: meta_type::<()>(),
+					docs: maybe_docs(vec![" Initialize a block with the given header."]),
+				},
+			],
+			docs: maybe_docs(vec![
+				" The `Core` runtime api that every Substrate runtime needs to implement.",
+			]),
+		},
+	];
+
+	let rt = Runtime;
+	let runtime_metadata = (&rt).runtime_metadata();
+	assert_eq!(runtime_metadata, expected_runtime_metadata);
+}
@@ -23,7 +23,8 @@ sp-state-machine = { version = "0.13.0", default-features = false, optional = tr
 sp-trie = { version = "7.0.0", default-features = false, optional = true, path = "../trie" }
 hash-db = { version = "0.16.0", optional = true }
 thiserror = { version = "1.0.30", optional = true }
-
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+sp-metadata-ir = { version = "0.1.0", default-features = false, path = "../metadata-ir" }
 log = { version = "0.4.17", default-features = false }

 [dev-dependencies]
@@ -42,6 +43,8 @@ std = [
 	"hash-db",
 	"thiserror",
 	"log/std",
+	"scale-info/std",
+	"sp-metadata-ir/std",
 ]
 # Special feature to disable logging completly.
 #
@@ -51,3 +54,5 @@ std = [
 #
 # This sets the max logging level to `off` for `log`.
 disable-logging = ["log/max_level_off"]
+# Do not report the documentation in the metadata.
+no-metadata-docs = []
@@ -24,6 +24,9 @@ proc-macro-crate = "1.1.3"
 expander = "1.0.0"
 Inflector = "0.11.4"

+[dev-dependencies]
+assert_matches = "1.3.0"
+
 # Required for the doc tests
 [features]
 default = ["std"]
@@ -15,16 +15,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-use crate::utils::{
-	extract_parameter_names_types_and_borrows, fold_fn_decl_for_client_side, generate_crate_access,
-	generate_runtime_mod_name_for_trait, parse_runtime_api_version, prefix_function_with_trait,
-	replace_wild_card_parameter_names, return_type_extract_type, versioned_trait_name,
-	AllowSelfRefInParameters,
-};
-
-use crate::common::{
-	API_VERSION_ATTRIBUTE, BLOCK_GENERIC_IDENT, CHANGED_IN_ATTRIBUTE, CORE_TRAIT_ATTRIBUTE,
-	RENAMED_ATTRIBUTE, SUPPORTED_ATTRIBUTE_NAMES,
+use crate::{
+	common::{
+		API_VERSION_ATTRIBUTE, BLOCK_GENERIC_IDENT, CHANGED_IN_ATTRIBUTE, CORE_TRAIT_ATTRIBUTE,
+		RENAMED_ATTRIBUTE, SUPPORTED_ATTRIBUTE_NAMES,
+	},
+	runtime_metadata::generate_decl_runtime_metadata,
+	utils::{
+		extract_parameter_names_types_and_borrows, fold_fn_decl_for_client_side,
+		generate_crate_access, generate_runtime_mod_name_for_trait, parse_runtime_api_version,
+		prefix_function_with_trait, replace_wild_card_parameter_names, return_type_extract_type,
+		versioned_trait_name, AllowSelfRefInParameters,
+	},
 };

 use proc_macro2::{Span, TokenStream};
@@ -219,6 +221,7 @@ fn generate_runtime_decls(decls: &[ItemTrait]) -> Result<TokenStream> {
 		let mut decl = decl.clone();
 		let decl_span = decl.span();
 		extend_generics_with_block(&mut decl.generics);
+		let metadata = generate_decl_runtime_metadata(&decl);
 		let mod_name = generate_runtime_mod_name_for_trait(&decl.ident);
 		let found_attributes = remove_supported_attributes(&mut decl.attrs);
 		let api_version =
@@ -304,6 +307,8 @@ fn generate_runtime_decls(decls: &[ItemTrait]) -> Result<TokenStream> {

 				pub use #versioned_ident as #main_api_ident;

+				#metadata
+
 				pub #api_version

 				pub #id
@@ -15,15 +15,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-use crate::utils::{
-	extract_all_signature_types, extract_block_type_from_trait_path, extract_impl_trait,
-	extract_parameter_names_types_and_borrows, generate_crate_access,
-	generate_runtime_mod_name_for_trait, parse_runtime_api_version, prefix_function_with_trait,
-	versioned_trait_name, AllowSelfRefInParameters, RequireQualifiedTraitPath,
+use crate::{
+	common::API_VERSION_ATTRIBUTE,
+	runtime_metadata::generate_impl_runtime_metadata,
+	utils::{
+		extract_all_signature_types, extract_block_type_from_trait_path, extract_impl_trait,
+		extract_parameter_names_types_and_borrows, generate_crate_access,
+		generate_runtime_mod_name_for_trait, parse_runtime_api_version, prefix_function_with_trait,
+		versioned_trait_name, AllowSelfRefInParameters, RequireQualifiedTraitPath,
+	},
 };

-use crate::common::API_VERSION_ATTRIBUTE;
-
 use proc_macro2::{Span, TokenStream};

 use quote::quote;
@@ -685,6 +687,7 @@ fn impl_runtime_apis_impl_inner(api_impls: &[ItemImpl]) -> Result<TokenStream> {
 	let runtime_api_versions = generate_runtime_api_versions(api_impls)?;
 	let wasm_interface = generate_wasm_interface(api_impls)?;
 	let api_impls_for_runtime_api = generate_api_impl_for_runtime_api(api_impls)?;
+	let runtime_metadata = generate_impl_runtime_metadata(api_impls)?;

 	let impl_ = quote!(
 		#base_runtime_api
@@ -695,6 +698,8 @@ fn impl_runtime_apis_impl_inner(api_impls: &[ItemImpl]) -> Result<TokenStream> {

 		#runtime_api_versions

+		#runtime_metadata
+
 		pub mod api {
 			use super::*;

@@ -25,6 +25,7 @@ mod common;
 mod decl_runtime_apis;
 mod impl_runtime_apis;
 mod mock_impl_runtime_apis;
+mod runtime_metadata;
 mod utils;

 #[proc_macro]
@@ -0,0 +1,271 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use proc_macro2::TokenStream as TokenStream2;
+use quote::quote;
+use syn::{parse_quote, ItemImpl, ItemTrait, Result};
+
+use crate::{
+	common::CHANGED_IN_ATTRIBUTE,
+	utils::{
+		extract_impl_trait, filter_cfg_attributes, generate_crate_access,
+		generate_runtime_mod_name_for_trait, get_doc_literals, RequireQualifiedTraitPath,
+	},
+};
+
+/// Get the type parameter argument without lifetime or mutability
+/// of a runtime metadata function.
+///
+/// In the following example, both the `AccountId` and `Index` generic
+/// type parameters must implement `scale_info::TypeInfo` because they
+/// are added into the metadata using `scale_info::meta_type`.
+///
+/// ```ignore
+/// trait ExampleAccountNonceApi<AccountId, Index> {
+///   fn account_nonce<'a>(account: &'a AccountId) -> Index;
+/// }
+/// ```
+///
+/// Instead of returning `&'a AccountId` for the first parameter, this function
+/// returns `AccountId` to place bounds around it.
+fn get_type_param(ty: &syn::Type) -> syn::Type {
+	// Remove the lifetime and mutability of the type T to
+	// place bounds around it.
+	let ty_elem = match &ty {
+		syn::Type::Reference(reference) => &reference.elem,
+		syn::Type::Ptr(ptr) => &ptr.elem,
+		syn::Type::Slice(slice) => &slice.elem,
+		syn::Type::Array(arr) => &arr.elem,
+		_ => ty,
+	};
+
+	ty_elem.clone()
+}
+
+/// Extract the documentation from the provided attributes.
+///
+/// It takes into account the `no-metadata-docs` feature.
+fn collect_docs(attrs: &[syn::Attribute], crate_: &TokenStream2) -> TokenStream2 {
+	if cfg!(feature = "no-metadata-docs") {
+		quote!(#crate_::vec![])
+	} else {
+		let docs = get_doc_literals(&attrs);
+		quote!(#crate_::vec![ #( #docs, )* ])
+	}
+}
+
+/// Generate the runtime metadata of the provided trait.
+///
+/// The metadata is exposed as a generic function on the hidden module
+/// of the trait generated by the `decl_runtime_apis`.
+pub fn generate_decl_runtime_metadata(decl: &ItemTrait) -> TokenStream2 {
+	let crate_ = generate_crate_access();
+	let mut methods = Vec::new();
+
+	// Ensure that any function parameter that relies on the `BlockT` bounds
+	// also has `TypeInfo + 'static` bounds (required by `scale_info::meta_type`).
+	//
+	// For example, if a runtime API defines a method that has an input:
+	// `fn func(input: <Block as BlockT>::Header)`
+	// then the runtime metadata will imply `<Block as BlockT>::Header: TypeInfo + 'static`.
+	//
+	// This restricts the bounds at the metadata level, without needing to modify the `BlockT`
+	// itself, since the concrete implementations are already satisfying `TypeInfo`.
+	let mut where_clause = Vec::new();
+	for item in &decl.items {
+		// Collect metadata for methods only.
+		let syn::TraitItem::Method(method) = item else {
+			continue
+		};
+
+		// Collect metadata only for the latest methods.
+		let is_changed_in =
+			method.attrs.iter().any(|attr| attr.path.is_ident(CHANGED_IN_ATTRIBUTE));
+		if is_changed_in {
+			continue
+		}
+
+		let mut inputs = Vec::new();
+		let signature = &method.sig;
+		for input in &signature.inputs {
+			// Exclude `self` from metadata collection.
+			let syn::FnArg::Typed(typed) = input else {
+				continue
+			};
+
+			let pat = &typed.pat;
+			let name = quote!(#pat).to_string();
+			let ty = &typed.ty;
+
+			where_clause.push(get_type_param(ty));
+
+			inputs.push(quote!(
+				#crate_::metadata_ir::RuntimeApiMethodParamMetadataIR {
+					name: #name,
+					ty: #crate_::scale_info::meta_type::<#ty>(),
+				}
+			));
+		}
+
+		let output = match &signature.output {
+			syn::ReturnType::Default => quote!(#crate_::scale_info::meta_type::<()>()),
+			syn::ReturnType::Type(_, ty) => {
+				where_clause.push(get_type_param(ty));
+				quote!(#crate_::scale_info::meta_type::<#ty>())
+			},
+		};
+
+		// String method name including quotes for constructing `v15::RuntimeApiMethodMetadata`.
+		let method_name = signature.ident.to_string();
+		let docs = collect_docs(&method.attrs, &crate_);
+
+		// Include the method metadata only if its `cfg` features are enabled.
+		let attrs = filter_cfg_attributes(&method.attrs);
+		methods.push(quote!(
+			#( #attrs )*
+			#crate_::metadata_ir::RuntimeApiMethodMetadataIR {
+				name: #method_name,
+				inputs: #crate_::vec![ #( #inputs, )* ],
+				output: #output,
+				docs: #docs,
+			}
+		));
+	}
+
+	let trait_name_ident = &decl.ident;
+	let trait_name = trait_name_ident.to_string();
+	let docs = collect_docs(&decl.attrs, &crate_);
+	let attrs = filter_cfg_attributes(&decl.attrs);
+	// The trait generics where already extended with `Block: BlockT`.
+	let mut generics = decl.generics.clone();
+	for generic_param in generics.params.iter_mut() {
+		let syn::GenericParam::Type(ty) = generic_param else {
+			continue
+		};
+
+		// Default type parameters are not allowed in functions.
+		ty.eq_token = None;
+		ty.default = None;
+	}
+
+	let where_clause = where_clause
+		.iter()
+		.map(|ty| quote!(#ty: #crate_::scale_info::TypeInfo + 'static));
+
+	quote!(
+		#( #attrs )*
+		#[inline(always)]
+		pub fn runtime_metadata #generics () -> #crate_::metadata_ir::RuntimeApiMetadataIR
+		where #( #where_clause, )*
+		{
+			#crate_::metadata_ir::RuntimeApiMetadataIR {
+				name: #trait_name,
+				methods: #crate_::vec![ #( #methods, )* ],
+				docs: #docs,
+			}
+		}
+	)
+}
+
+/// Implement the `runtime_metadata` function on the runtime that
+/// generates the metadata for the given traits.
+///
+/// The metadata of each trait is extracted from the generic function
+/// exposed by `generate_decl_runtime_metadata`.
+pub fn generate_impl_runtime_metadata(impls: &[ItemImpl]) -> Result<TokenStream2> {
+	if impls.is_empty() {
+		return Ok(quote!())
+	}
+
+	let crate_ = generate_crate_access();
+
+	// Get the name of the runtime for which the traits are implemented.
+	let runtime_name = &impls
+		.get(0)
+		.expect("Traits should contain at least one implementation; qed")
+		.self_ty;
+
+	let mut metadata = Vec::new();
+
+	for impl_ in impls {
+		let mut trait_ = extract_impl_trait(&impl_, RequireQualifiedTraitPath::Yes)?.clone();
+
+		// Implementation traits are always references with a path `impl client::Core<generics> ...`
+		// The trait name is the last segment of this path.
+		let trait_name_ident = &trait_
+			.segments
+			.last()
+			.as_ref()
+			.expect("Trait path should always contain at least one item; qed")
+			.ident;
+
+		// Extract the generics from the trait to pass to the `runtime_metadata`
+		// function on the hidden module.
+		let generics = trait_
+			.segments
+			.iter()
+			.find_map(|segment| {
+				if let syn::PathArguments::AngleBracketed(generics) = &segment.arguments {
+					Some(generics.clone())
+				} else {
+					None
+				}
+			})
+			.expect("Trait path should always contain at least one generic parameter; qed");
+
+		let mod_name = generate_runtime_mod_name_for_trait(&trait_name_ident);
+		// Get absolute path to the `runtime_decl_for_` module by replacing the last segment.
+		if let Some(segment) = trait_.segments.last_mut() {
+			*segment = parse_quote!(#mod_name);
+		}
+
+		let attrs = filter_cfg_attributes(&impl_.attrs);
+		metadata.push(quote!(
+			#( #attrs )*
+			#trait_::runtime_metadata::#generics()
+		));
+	}
+
+	// Each runtime must expose the `runtime_metadata()` to fetch the runtime API metadata.
+	// The function is implemented by calling `impl_runtime_apis!`.
+	//
+	// However, the `construct_runtime!` may be called without calling `impl_runtime_apis!`.
+	// Rely on the `Deref` trait to differentiate between a runtime that implements
+	// APIs (by macro impl_runtime_apis!) and a runtime that is simply created (by macro
+	// construct_runtime!).
+	//
+	// Both `InternalConstructRuntime` and `InternalImplRuntimeApis` expose a `runtime_metadata()`
+	// function. `InternalConstructRuntime` is implemented by the `construct_runtime!` for Runtime
+	// references (`& Runtime`), while `InternalImplRuntimeApis` is implemented by the
+	// `impl_runtime_apis!` for Runtime (`Runtime`).
+	//
+	// Therefore, the `Deref` trait will resolve the `runtime_metadata` from `impl_runtime_apis!`
+	// when both macros are called; and will resolve an empty `runtime_metadata` when only the
+	// `construct_runtime!` is called.
+
+	Ok(quote!(
+		#[doc(hidden)]
+		trait InternalImplRuntimeApis {
+			#[inline(always)]
+			fn runtime_metadata(&self) -> #crate_::vec::Vec<#crate_::metadata_ir::RuntimeApiMetadataIR> {
+				#crate_::vec![ #( #metadata, )* ]
+			}
+		}
+		#[doc(hidden)]
+		impl InternalImplRuntimeApis for #runtime_name {}
+	))
+}
@@ -253,7 +253,74 @@ pub fn parse_runtime_api_version(version: &Attribute) -> Result<u64> {
 	version.base10_parse()
 }

-// Each versioned trait is named 'ApiNameVN' where N is the specific version. E.g. ParachainHostV2
+/// Each versioned trait is named 'ApiNameVN' where N is the specific version. E.g. ParachainHostV2
 pub fn versioned_trait_name(trait_ident: &Ident, version: u64) -> Ident {
 	format_ident!("{}V{}", trait_ident, version)
 }
+
+/// Extract the documentation from the provided attributes.
+pub fn get_doc_literals(attrs: &[syn::Attribute]) -> Vec<syn::Lit> {
+	attrs
+		.iter()
+		.filter_map(|attr| {
+			let Ok(syn::Meta::NameValue(meta)) = attr.parse_meta() else {
+				return None
+			};
+
+			meta.path.get_ident().filter(|ident| *ident == "doc").map(|_| meta.lit)
+		})
+		.collect()
+}
+
+/// Filters all attributes except the cfg ones.
+pub fn filter_cfg_attributes(attrs: &[syn::Attribute]) -> Vec<syn::Attribute> {
+	attrs.iter().filter(|a| a.path.is_ident("cfg")).cloned().collect()
+}
+
+#[cfg(test)]
+mod tests {
+	use assert_matches::assert_matches;
+
+	use super::*;
+
+	#[test]
+	fn check_get_doc_literals() {
+		const FIRST: &'static str = "hello";
+		const SECOND: &'static str = "WORLD";
+
+		let doc: Attribute = parse_quote!(#[doc = #FIRST]);
+		let doc_world: Attribute = parse_quote!(#[doc = #SECOND]);
+
+		let attrs = vec![
+			doc.clone(),
+			parse_quote!(#[derive(Debug)]),
+			parse_quote!(#[test]),
+			parse_quote!(#[allow(non_camel_case_types)]),
+			doc_world.clone(),
+		];
+
+		let docs = get_doc_literals(&attrs);
+		assert_eq!(docs.len(), 2);
+		assert_matches!(&docs[0], syn::Lit::Str(val) if val.value() == FIRST);
+		assert_matches!(&docs[1], syn::Lit::Str(val) if val.value() == SECOND);
+	}
+
+	#[test]
+	fn check_filter_cfg_attributes() {
+		let cfg_std: Attribute = parse_quote!(#[cfg(feature = "std")]);
+		let cfg_benchmarks: Attribute = parse_quote!(#[cfg(feature = "runtime-benchmarks")]);
+
+		let attrs = vec![
+			cfg_std.clone(),
+			parse_quote!(#[derive(Debug)]),
+			parse_quote!(#[test]),
+			cfg_benchmarks.clone(),
+			parse_quote!(#[allow(non_camel_case_types)]),
+		];
+
+		let filtered = filter_cfg_attributes(&attrs);
+		assert_eq!(filtered.len(), 2);
+		assert_eq!(cfg_std, filtered[0]);
+		assert_eq!(cfg_benchmarks, filtered[1]);
+	}
+}
@@ -76,12 +76,16 @@ pub use codec::{self, Decode, DecodeLimit, Encode};
 #[cfg(feature = "std")]
 pub use hash_db::Hasher;
 #[doc(hidden)]
+pub use scale_info;
+#[doc(hidden)]
 #[cfg(not(feature = "std"))]
 pub use sp_core::to_substrate_wasm_fn_return_value;
 use sp_core::OpaqueMetadata;
 #[doc(hidden)]
 pub use sp_core::{offchain, ExecutionContext};
 #[doc(hidden)]
+pub use sp_metadata_ir::{self as metadata_ir, frame_metadata as metadata};
+#[doc(hidden)]
 #[cfg(feature = "std")]
 pub use sp_runtime::StateVersion;
 #[doc(hidden)]
@@ -101,7 +105,7 @@ pub use sp_state_machine::{
 	StorageProof, TrieBackend, TrieBackendBuilder,
 };
 #[doc(hidden)]
-pub use sp_std::{mem, slice};
+pub use sp_std::{mem, slice, vec};
 #[doc(hidden)]
 pub use sp_version::{create_apis_vec, ApiId, ApisVec, RuntimeVersion};
 #[cfg(feature = "std")]
@@ -284,7 +284,7 @@ impl<AuthorityId> OnNewValidatorSet<AuthorityId> for () {
 /// the runtime API boundary this type is unknown and as such we keep this
 /// opaque representation, implementors of the runtime API will have to make
 /// sure that all usages of `OpaqueKeyOwnershipProof` refer to the same type.
-#[derive(Decode, Encode, PartialEq)]
+#[derive(Decode, Encode, PartialEq, TypeInfo)]
 pub struct OpaqueKeyOwnershipProof(Vec<u8>);
 impl OpaqueKeyOwnershipProof {
 	/// Create a new `OpaqueKeyOwnershipProof` using the given encoded
@@ -0,0 +1,28 @@
+[package]
+name = "sp-metadata-ir"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://substrate.io"
+repository = "https://github.com/paritytech/substrate/"
+description = "Intermediate representation of the runtime metadata."
+documentation = "https://docs.rs/sp-metadata-ir"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.2.2", default-features = false }
+frame-metadata = { version = "15.1.0", default-features = false, features = ["v14", "v15-unstable"] }
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+sp-std = { version = "5.0.0", default-features = false, path = "../std" }
+
+[features]
+default = ["std"]
+std = [
+	"codec/std",
+	"frame-metadata/std",
+	"scale-info/std",
+	"sp-std/std",
+]
@@ -17,15 +17,28 @@

 //! Intermediate representation of the runtime metadata.

+#![cfg_attr(not(feature = "std"), no_std)]
+#![warn(missing_docs)]
+
+// Re-export.
+#[doc(hidden)]
+pub use frame_metadata;
+
 mod types;
 use frame_metadata::{RuntimeMetadataPrefixed, RuntimeMetadataV14};
 pub use types::*;

 mod v14;
+mod v15;

 /// Metadata V14.
 const V14: u32 = 14;

+/// Metadata V15.
+///
+/// Not yet stable, thus we set it to `u32::MAX`.
+const V15: u32 = u32::MAX;
+
 /// Transform the IR to the specified version.
 ///
 /// Use [`supported_versions`] to find supported versions.
@@ -36,13 +49,18 @@ pub fn into_version(metadata: MetadataIR, version: u32) -> Option<RuntimeMetadat
 			let v14: frame_metadata::v14::RuntimeMetadataV14 = metadata.into();
 			Some(v14.into())
 		},
+		// Unstable metadata.
+		V15 => {
+			let v15: frame_metadata::v15::RuntimeMetadataV15 = metadata.into();
+			Some(v15.into())
+		},
 		_ => None,
 	}
 }

 /// Returns the supported metadata versions.
 pub fn supported_versions() -> sp_std::vec::Vec<u32> {
-	sp_std::vec![V14,]
+	sp_std::vec![V14, V15]
 }

 /// Transform the IR to the latest stable metadata version.
@@ -54,7 +72,6 @@ pub fn into_latest(metadata: MetadataIR) -> RuntimeMetadataPrefixed {
 #[cfg(test)]
 mod test {
 	use super::*;
-	use crate::metadata_ir::ExtrinsicMetadataIR;
 	use frame_metadata::{v14::META_RESERVED, RuntimeMetadata};
 	use scale_info::meta_type;

@@ -67,6 +84,7 @@ mod test {
 				signed_extensions: vec![],
 			},
 			ty: meta_type::<()>(),
+			apis: vec![],
 		}
 	}

@@ -79,4 +97,14 @@ mod test {

 		assert!(matches!(metadata.1, RuntimeMetadata::V14(_)));
 	}
+
+	#[test]
+	fn into_version_15() {
+		let ir = ir_metadata();
+		let metadata = into_version(ir, V15).expect("Should return prefixed metadata");
+
+		assert_eq!(metadata.0, META_RESERVED);
+
+		assert!(matches!(metadata.1, RuntimeMetadata::V15(_)));
+	}
 }
@@ -37,6 +37,77 @@ pub struct MetadataIR<T: Form = MetaForm> {
 	pub extrinsic: ExtrinsicMetadataIR<T>,
 	/// The type of the `Runtime`.
 	pub ty: T::Type,
+	/// Metadata of the Runtime API.
+	pub apis: Vec<RuntimeApiMetadataIR<T>>,
+}
+
+/// Metadata of a runtime trait.
+#[derive(Clone, PartialEq, Eq, Encode, Debug)]
+pub struct RuntimeApiMetadataIR<T: Form = MetaForm> {
+	/// Trait name.
+	pub name: T::String,
+	/// Trait methods.
+	pub methods: Vec<RuntimeApiMethodMetadataIR<T>>,
+	/// Trait documentation.
+	pub docs: Vec<T::String>,
+}
+
+impl IntoPortable for RuntimeApiMetadataIR {
+	type Output = RuntimeApiMetadataIR<PortableForm>;
+
+	fn into_portable(self, registry: &mut Registry) -> Self::Output {
+		RuntimeApiMetadataIR {
+			name: self.name.into_portable(registry),
+			methods: registry.map_into_portable(self.methods),
+			docs: registry.map_into_portable(self.docs),
+		}
+	}
+}
+
+/// Metadata of a runtime method.
+#[derive(Clone, PartialEq, Eq, Encode, Debug)]
+pub struct RuntimeApiMethodMetadataIR<T: Form = MetaForm> {
+	/// Method name.
+	pub name: T::String,
+	/// Method parameters.
+	pub inputs: Vec<RuntimeApiMethodParamMetadataIR<T>>,
+	/// Method output.
+	pub output: T::Type,
+	/// Method documentation.
+	pub docs: Vec<T::String>,
+}
+
+impl IntoPortable for RuntimeApiMethodMetadataIR {
+	type Output = RuntimeApiMethodMetadataIR<PortableForm>;
+
+	fn into_portable(self, registry: &mut Registry) -> Self::Output {
+		RuntimeApiMethodMetadataIR {
+			name: self.name.into_portable(registry),
+			inputs: registry.map_into_portable(self.inputs),
+			output: registry.register_type(&self.output),
+			docs: registry.map_into_portable(self.docs),
+		}
+	}
+}
+
+/// Metadata of a runtime method parameter.
+#[derive(Clone, PartialEq, Eq, Encode, Debug)]
+pub struct RuntimeApiMethodParamMetadataIR<T: Form = MetaForm> {
+	/// Parameter name.
+	pub name: T::String,
+	/// Parameter type.
+	pub ty: T::Type,
+}
+
+impl IntoPortable for RuntimeApiMethodParamMetadataIR {
+	type Output = RuntimeApiMethodParamMetadataIR<PortableForm>;
+
+	fn into_portable(self, registry: &mut Registry) -> Self::Output {
+		RuntimeApiMethodParamMetadataIR {
+			name: self.name.into_portable(registry),
+			ty: registry.register_type(&self.ty),
+		}
+	}
 }

 /// The intermediate representation for a pallet metadata.
@@ -0,0 +1,188 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Convert the IR to V15 metadata.
+
+use super::types::{
+	ExtrinsicMetadataIR, MetadataIR, PalletCallMetadataIR, PalletConstantMetadataIR,
+	PalletErrorMetadataIR, PalletEventMetadataIR, PalletMetadataIR, PalletStorageMetadataIR,
+	RuntimeApiMetadataIR, RuntimeApiMethodMetadataIR, RuntimeApiMethodParamMetadataIR,
+	SignedExtensionMetadataIR, StorageEntryMetadataIR, StorageEntryModifierIR, StorageEntryTypeIR,
+	StorageHasherIR,
+};
+
+use frame_metadata::v15::{
+	ExtrinsicMetadata, PalletCallMetadata, PalletConstantMetadata, PalletErrorMetadata,
+	PalletEventMetadata, PalletMetadata, PalletStorageMetadata, RuntimeApiMetadata,
+	RuntimeApiMethodMetadata, RuntimeApiMethodParamMetadata, RuntimeMetadataV15,
+	SignedExtensionMetadata, StorageEntryMetadata, StorageEntryModifier, StorageEntryType,
+	StorageHasher,
+};
+
+impl From<MetadataIR> for RuntimeMetadataV15 {
+	fn from(ir: MetadataIR) -> Self {
+		RuntimeMetadataV15::new(
+			ir.pallets.into_iter().map(Into::into).collect(),
+			ir.extrinsic.into(),
+			ir.ty,
+			ir.apis.into_iter().map(Into::into).collect(),
+		)
+	}
+}
+
+impl From<RuntimeApiMetadataIR> for RuntimeApiMetadata {
+	fn from(ir: RuntimeApiMetadataIR) -> Self {
+		RuntimeApiMetadata {
+			name: ir.name,
+			methods: ir.methods.into_iter().map(Into::into).collect(),
+			docs: ir.docs,
+		}
+	}
+}
+
+impl From<RuntimeApiMethodMetadataIR> for RuntimeApiMethodMetadata {
+	fn from(ir: RuntimeApiMethodMetadataIR) -> Self {
+		RuntimeApiMethodMetadata {
+			name: ir.name,
+			inputs: ir.inputs.into_iter().map(Into::into).collect(),
+			output: ir.output,
+			docs: ir.docs,
+		}
+	}
+}
+
+impl From<RuntimeApiMethodParamMetadataIR> for RuntimeApiMethodParamMetadata {
+	fn from(ir: RuntimeApiMethodParamMetadataIR) -> Self {
+		RuntimeApiMethodParamMetadata { name: ir.name, ty: ir.ty }
+	}
+}
+
+impl From<PalletMetadataIR> for PalletMetadata {
+	fn from(ir: PalletMetadataIR) -> Self {
+		PalletMetadata {
+			name: ir.name,
+			storage: ir.storage.map(Into::into),
+			calls: ir.calls.map(Into::into),
+			event: ir.event.map(Into::into),
+			constants: ir.constants.into_iter().map(Into::into).collect(),
+			error: ir.error.map(Into::into),
+			index: ir.index,
+			docs: ir.docs,
+		}
+	}
+}
+
+impl From<StorageEntryModifierIR> for StorageEntryModifier {
+	fn from(ir: StorageEntryModifierIR) -> Self {
+		match ir {
+			StorageEntryModifierIR::Optional => StorageEntryModifier::Optional,
+			StorageEntryModifierIR::Default => StorageEntryModifier::Default,
+		}
+	}
+}
+
+impl From<StorageHasherIR> for StorageHasher {
+	fn from(ir: StorageHasherIR) -> Self {
+		match ir {
+			StorageHasherIR::Blake2_128 => StorageHasher::Blake2_128,
+			StorageHasherIR::Blake2_256 => StorageHasher::Blake2_256,
+			StorageHasherIR::Blake2_128Concat => StorageHasher::Blake2_128Concat,
+			StorageHasherIR::Twox128 => StorageHasher::Twox128,
+			StorageHasherIR::Twox256 => StorageHasher::Twox256,
+			StorageHasherIR::Twox64Concat => StorageHasher::Twox64Concat,
+			StorageHasherIR::Identity => StorageHasher::Identity,
+		}
+	}
+}
+
+impl From<StorageEntryTypeIR> for StorageEntryType {
+	fn from(ir: StorageEntryTypeIR) -> Self {
+		match ir {
+			StorageEntryTypeIR::Plain(ty) => StorageEntryType::Plain(ty),
+			StorageEntryTypeIR::Map { hashers, key, value } => StorageEntryType::Map {
+				hashers: hashers.into_iter().map(Into::into).collect(),
+				key,
+				value,
+			},
+		}
+	}
+}
+
+impl From<StorageEntryMetadataIR> for StorageEntryMetadata {
+	fn from(ir: StorageEntryMetadataIR) -> Self {
+		StorageEntryMetadata {
+			name: ir.name,
+			modifier: ir.modifier.into(),
+			ty: ir.ty.into(),
+			default: ir.default,
+			docs: ir.docs,
+		}
+	}
+}
+
+impl From<PalletStorageMetadataIR> for PalletStorageMetadata {
+	fn from(ir: PalletStorageMetadataIR) -> Self {
+		PalletStorageMetadata {
+			prefix: ir.prefix,
+			entries: ir.entries.into_iter().map(Into::into).collect(),
+		}
+	}
+}
+
+impl From<PalletCallMetadataIR> for PalletCallMetadata {
+	fn from(ir: PalletCallMetadataIR) -> Self {
+		PalletCallMetadata { ty: ir.ty }
+	}
+}
+
+impl From<PalletEventMetadataIR> for PalletEventMetadata {
+	fn from(ir: PalletEventMetadataIR) -> Self {
+		PalletEventMetadata { ty: ir.ty }
+	}
+}
+
+impl From<PalletConstantMetadataIR> for PalletConstantMetadata {
+	fn from(ir: PalletConstantMetadataIR) -> Self {
+		PalletConstantMetadata { name: ir.name, ty: ir.ty, value: ir.value, docs: ir.docs }
+	}
+}
+
+impl From<PalletErrorMetadataIR> for PalletErrorMetadata {
+	fn from(ir: PalletErrorMetadataIR) -> Self {
+		PalletErrorMetadata { ty: ir.ty }
+	}
+}
+
+impl From<SignedExtensionMetadataIR> for SignedExtensionMetadata {
+	fn from(ir: SignedExtensionMetadataIR) -> Self {
+		SignedExtensionMetadata {
+			identifier: ir.identifier,
+			ty: ir.ty,
+			additional_signed: ir.additional_signed,
+		}
+	}
+}
+
+impl From<ExtrinsicMetadataIR> for ExtrinsicMetadata {
+	fn from(ir: ExtrinsicMetadataIR) -> Self {
+		ExtrinsicMetadata {
+			ty: ir.ty,
+			version: ir.version,
+			signed_extensions: ir.signed_extensions.into_iter().map(Into::into).collect(),
+		}
+	}
+}
@@ -13,6 +13,7 @@ targets = ["x86_64-unknown-linux-gnu"]

 [dependencies]
 codec = { package = "parity-scale-codec", version = "3.2.2", default-features = false, features = ["derive"] }
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
 serde = { version = "1.0.136", features = ["derive"], optional = true }
 sp-application-crypto = { version = "7.0.0", default-features = false, path = "../application-crypto" }
 sp-core = { version = "7.0.0", default-features = false, path = "../core" }
@@ -28,4 +29,5 @@ std = [
 	"sp-application-crypto/std",
 	"sp-core/std",
 	"sp-runtime/std",
+	"scale-info/std",
 ]
@@ -28,7 +28,7 @@ pub use sp_core::{hash::H256, RuntimeDebug};
 use sp_runtime::traits::{BlakeTwo256, Extrinsic as ExtrinsicT, Verify};

 /// Extrinsic for test-runtime.
-#[derive(Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug)]
+#[derive(Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug, scale_info::TypeInfo)]
 pub enum Extrinsic {
 	IncludeData(Vec<u8>),
 	StorageChange(Vec<u8>, Option<Vec<u8>>),